The present invention relates in general to surgical instruments, and more particularly to minimally invasive surgical instruments capable of recording various conditions of the instrument.
The disclosed invention relates generally and in various embodiments to surgical stapling and cutting instruments structured and configured for applying lines of staples from a reusable staple cartridge into tissue while cutting the tissue between the applied staple lines. More particularly the disclosed invention relates to electronic interlocks for use in motorized surgical stapling and cutting instruments that prevent cutting of the tissue when the staple cartridge is not installed, is improperly installed, or is spent, or when the surgical stapling and cutting instrument is not otherwise in a condition to perform a stapling and cutting operation in a safe and/or optimal manner. The disclosed invention further relates to electronic interlocks for disabling use of certain instrument features while a stapling and cutting operation is in progress.
Endoscopic surgical instruments are often preferred over traditional open surgical devices because a smaller incision tends to reduce the post-operative recovery time and complications. Consequently, significant development has gone into a range of endoscopic surgical instruments that are suitable for precise placement of a distal end effector at a desired surgical site through a cannula of a trocar. These distal end effectors engage the tissue in a number of ways to achieve a diagnostic or therapeutic effect (e.g., endocutter, grasper, cutter, staplers, clip applier, access device, drug/gene therapy delivery device, and energy device using ultrasound, RF, laser, etc.).
Known surgical staplers include an end effector that simultaneously makes a longitudinal incision in tissue and applies lines of staples on opposing sides of the incision. The end effector includes a pair of cooperating jaw members that, if the instrument is intended for endoscopic or laparoscopic applications, are capable of passing through a cannula passageway. One of the jaw members receives a staple cartridge having at least two laterally spaced rows of staples. The other jaw member defines an anvil having staple-forming pockets aligned with the rows of staples in the cartridge. The instrument includes a plurality of reciprocating wedges which, when driven distally, pass through openings in the staple cartridge and engage drivers supporting the staples to effect the firing of the staples toward the anvil.
An example of a surgical stapler suitable for endoscopic applications is described in U.S. Pat. No. 5,465,895, entitled “SURGICAL STAPLER INSTRUMENT” to Knodel et al., which discloses an endocutter with distinct closing and firing actions. A clinician using this device is able to close the jaw members upon tissue to position the tissue prior to firing. Once the clinician has determined that the jaw members are properly gripping tissue, the clinician can then fire the surgical stapler with a single firing stroke, or multiple firing strokes, depending on the device. Firing the surgical stapler causes severing and stapling of the tissue. The simultaneous severing and stapling avoids complications that may arise when performing such actions sequentially with different surgical tools that respectively only sever and staple.
One specific advantage of being able to close upon tissue before firing is that the clinician is able to verify via an endoscope that the desired location for the cut has been achieved, including a sufficient amount of tissue has been captured between opposing jaws. Otherwise, opposing jaws may be drawn too close together, especially pinching at their distal ends, and thus not effectively forming closed staples in the severed tissue. At the other extreme, an excessive amount of clamped tissue may cause binding and an incomplete firing.
When endoscopic surgical instruments fail, they are often returned to the manufacturer, or other entity, for analysis of the failure. If the failure resulted in a critical class of defect in the instrument, it is necessary for the manufacturer to determine the cause of the failure and determine whether a design change is required. In that case, the manufacturer may spend many hundreds of man-hours analyzing a failed instrument and attempting to reconstruct the conditions under which it failed based only on the damage to the instrument. It can be expensive and very challenging to analyze instrument failures in this way. Also, many of these analyses simply conclude that the failure was due to improper use of the instrument.
Because the actuating force (i.e., the “force-to-fire”, or FTF) necessary to close the jaws and simultaneously perform the cutting and stapling operation may be considerable, a manually-powered cutting and stapling instrument such as that described above may not be utilizable by otherwise qualified users who are unable to generate the required FTF. Accordingly, powered cutting and stapling instruments have been developed for decreasing the force-to-fire (FTF). Such instruments typically incorporate motors or other actuating mechanisms suitable for supplementing or replacing user-generated force for performing the cutting and stapling operation.
Although powered instruments provide numerous advantages, it is desirable to prevent inadvertent firing of the instrument under certain conditions. For example, firing the instrument without having a staple cartridge installed, or firing the instrument having an installed but spent staple cartridge, may result in cutting of tissue without simultaneous stapling to minimize bleeding. Additionally, firing of the instrument without proper closure of the jaw members may result in an unacceptable cutting and stapling operation and/or cause mechanical damage to the instrument. Similar consequences may result if the jaw members are inadvertently opened while a cutting and stapling operation is in progress. It is particularly desirable that interlock features for preventing such inadvertent firing and jaw manipulation be accomplished in a reliable way that is not subject to an intervening malfunction. Moreover, for ease of manufacturing and assembly, it is further desirable that the interlock features be accomplished with a minimum number of components.
Consequently, a significant need exists for electronic interlock features for use in powered cutting and stapling instruments that prevent inadvertent firing (i.e., cutting and stapling) and jaw manipulation during conditions such as those described above.